Apparatus for copper welding or heat treating tubing or other long lengths of metal



March 28, 1939- B. 1 QUARNSTROM APPARATUS FOR COPPER WELDING OR HEAT TREATING TUBING OR OTHER LONG' LENGTHS OF METAL Filed NOV, 16. 1935 3 Sheets-Sheet 3 ATTORNEYS.

Patented Mar.' 28, 1939 PATENT OFFICE .PPARATUS FOR COPPER WELDING R HEAT TREATING LONG TUBING 0R` OTHER LENG'rHs or METAL Bert L. Quarnstrom, Detroit, Mich., assignor to Bundy Tubing Company, Detroit, Mich., a corporation of Michigan Application November 1e, 1935, serial No; 59,212

'l Claims.

This invention relates to van apparatus for heating by electrical resistance and then, cooling, long lengths of material such as tube, rods, wire, or strip stock, or the like. Y

The apparatus is particularly useful in the manufacture of tubing which is fashioned from strip stock into tubular form and which, by means of the apparatus shown herein, is heated byelectrical resistance so that overlapping or contacting surfaces of the stock are fused together. Specifically, a tube is referred to which has a seam or seams or overlapping' parts or plies united by copper which has been rendered molten, and which may be made from copper coated strip stock. Such as the tube disclosed in the Harry W. Bundy Patent No. 1,930,191, of October 10, 1933. The basic metal of the strip may be ferrous metal or other metal, such as .MoneL which has an affinity for copper. Z0 In the maklngof such a copper coated tube the tube is fed quite fast through the apparatus and the electrodes are spaced longitudinally on the tube. One ofthe principal problems is that of cooling the tube down to a suitable tempera- 25 ture before it is exposed to the atmosphere. If

the tube is exposed to the atmosphere after the molten copper has solidified but before the copper vis sufilciently cooled, the samewill rapidly oxidize, and the copper coating is rendered de- 30 fective or destroyed.` A cooling chamber of ordinary structure would have to be so long that it would be impractical to use the apparatus, where the tube moves at a relatively high rate of speed.

Therefore, I have attacked the problem of pro- 35 viding a method and an apparatus therefor,

which apparatus embodies a particular form of cooling devicewhich includes a preliminary cool..

ing of the tube and then a quenching of the tube,

to the end that the total length of the cooling 40 portion of the apparatus is materially reduced and the apparatus made practical for' making tube at a high rate of speed.

While in the description herein reference is made to tubing, it is to' be appreciated that the 45 apparatus is not limited to-the making of tubing. For example, the copper coating on a wire,

rod, strip stock, or a coating on a sealed tube may be afiixed to the underlying metal by heating the same, so that the copper alloys with the under- 50 lying metal. In this event a welding operation is not contemplated and the heats employed may 'I or may not be above copper melting temperature. Nevertheless, the problem of cooling is present and the apparatus may be effectively used for treat- 55 lng such materials. Moreover, the apparatus may be used inl annealing tube previously sealed with copper and which may 'be coated with copper.

For example, in `making small tube, a copper' coated copper sealed tube may be made, and then f drawn down to size. The drawn tube may then be run through the apparatus with the heat treatment arranged to annal the steel, and the apparatus then meets the again present problem of cooling. These are the general objects of `the invention, and others will appear as the detailed description progresses.

Fig. 1 is a side elevational view showing a structure embodying the invention.

Fig. 2 is an enlarged vview largely in section showing part of the cooler of the device.

Fig. 3 is a cross sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is an enlarged view with parts in section and with parts out away illustrating the heating unit and electrical wiring system.

Fig. 5 is a detail view in cross section illustrating the quenching unit of the cooler.

Fig. 6 is a detail view largely in section showing the equipment used in the starting of the machine.

Fig. 7 is a detail view of some of the switch structure shown in Fig. 6, illustrating the switch in a different position.

Fig. 8 is a side elevational view of the apparatus shown in Fig. 6 looking from the left hand side thereof.

Fig. 9 is an enlarged sectional view of a controlling valve.

Referring to Fig. 1, the tube is shown at A and it moves from right to left between rollers I.

These rollers may be feeding rollers for feeding" a denite length of tube, or the final rollers of a tube machine which fashions the tube from strip stock. Tube machines of this type run quite fast and the apparatus is designed to co-operate with such tube machines, so that the tube may be heated to melt the sealing metal and seal and complete the tube all in one operation. The electrodes may be supported on a table or the like 2, and the electrodes are I)housed in boxes `or containers 3 and I. 'I'he device-may include another pair of driving rollers 5' and the tube may enter the box 3 through an inlet device 6. This inlet may be equipped with a swinging closure or door 1, which normally closes the inlet but which is automatically' opened as a tube enters. The boxes 3 and' 4 are connected by piping which' houses the tube as shown in Fig. 4. The tube may run directly through a pipe III surrounded by telescoping pipes Il and I2 joined by be adjusted toward and away from each other to adjust the distance between the electrodes; to this end the box 3 may have a screw threaded rod I5 projecting therefrom which cooperates -with the threaded nut (not shown) in housing i6,

lcoating in place on the surface ofthe tube, rod,

wire, strip or other material while the copper is molten. This, however, is covered in Patents 2.9091018 and 2,092,557, both dated September 7, 1 37.

Inside the box 3 is a roller electrode 2| which may be grooved to lit the tube, and the tube is held thereagainst by a spring pressed roller 22, the same being spring pressed by the structure shown, which includes the spring pressed plunger 23. The tube then passes through the pipe I0 and over a grooved roller electrode 24', and is likewise held thereagainst by a roller 25 held against the tube by a spring pressed plunger 26. The secondary circuit which carries a low voltage, high amperage current is connected to-these rollers, the circuit being illustrated at 30. 'I'he roller electrode 24 is preferably driven, as by means of a belt 21 extending from the shaft of one offthe driving rollers 6. Preferably, the arrangement is such that the surface speed of the roller 24 slightly exceeds that at which the tube moves. It willbe seen, therefore, that the tube is heated by an electrical current passing length' wise therethrough from one roller` electrode to another, and the tube in its movement passes from the box 4 into the cooling sections of the apparatus.

There are certain electrical controls and circuits, as illustrated, and switches which are controlled by the presence or absence of the tube; but before going into a description of the electrical phase of the matter the remaining structure of the apparatus, and especially the cooling section, will be described. l

A water jacketed unit of the cooler is connected in sealed relation to the box 4 and it comprises an outer jacket or pipe 3i and an inner pipe 32, with the inner `pipe held spaced from the outer pipe by suitable spcer'brackets 33. 'I'he inner pipe 32 may be joined directly to the box 4. A water supply main is illustrated at 35,

,and this may connect into the outer jacket at 'the left hand end or outgoing end thereof, as

shown in Fig. 2. The water passes through the unit between the inner and outer jackets and may discharge therefrom near the entrance end through pipe 36, and the water may be drained oil! as-waste through a drain pipe 31. Due to temperature changes, the inner and outer jackets are sealed together by means of an expansion joint 33, the details of which are shown in Fig. 2 and in connection with which a general reference is all that is necessary. Also, the inner jacket 32 is preferably divided for expansion and contraction, thus having a slip joint 39. Also, the apparatus is charged with a non-oxidizing or reducing gas such as hydrogen or a gas obtained by a slip joint or expansion joint i3. The boxes may` cracking ordinary illuminating gas, and generally called electrolene. A pipe 4B for such gas may be connected to the inner jacket 32 and extends out through a slot 4I in the outer jacket, which slot permits relative movement between the inner and outer jackets but which is sealed by a suitable gasket 42, held tight against the outer jacket by plate 43j which may be fastened to the outer jacket by. screw threaded studs 44 and nuts, as shown.

l A tank yof such gas is shown at 45 and a pipe 46 leads therefrom to a dryer 41, and which dryer comprises a,container of hygroscopic material, such as calcium chlorid, and the gas passes through the, same and then enters the box 3 through a pipe 43. Thus dry gas is passed into the chamber of highest temperature, thus minimizing the possibility of the collection of moisture. Pipe 46 connects into a pipe 50, which in turn leads into substantially the central portion of the quenching unit of the cooler. Also, pipe 46 connects to pipe 46, so that the gas is passed into the box 3, into the water cooler section of the cooler, and into the quenching section..

Most of the gases pass toward the left with the movement of the tube and burn off at burn of! pipe 5i, while some of the gases may burn of! at the extreme outlet end of the cooler section, as shown at 52 (Figs. 1 and 5).

The quenching section is illustrated in Fig. 5, and its entrance end has an extension 60 which is connected to the extension 6i on the outgoing end of the water cooled jacket, by a sleeve 62. This quenching section comprises an inner pipe 63, provided with openings in the form of longitudinal slots 64 and 65. 'I'his pipe is equipped with an inlet Adevice 66 for the tube, which substantially plugs the inlet end but has a relatively small port 61 which'fairly snugly ilts the tube. The outlet end of the pipe is provided with a titting 63 which has a relatively small tube aperture 69. The outer jacket of `the quenching device is advantageously composed of pipe sections and fittings in the nature 0f couplings and Ts. Such pipe sections are shown at 10, the couplings at 1I, and the T ttings at, 12. The couplings are associated with a. structure providing sealing joints as at 13, which substantially seal the space between the outer and inner jackets. A suitable liquid, such as oil, is forced into this quenching unit through a pipe 13 which is connected to one of the T fittings and the same discharges therefrom through pipes 16 and 11 connected to T fittings at opposite ends of the quenching unit. The pipe 53 for the non-oxidizing gas connects into the fourth T tting, as shown'.

A tube moves through the unit as shown in Fig. 5 from right to left, and to facilitate initial insertion of the tube therethrough the member 60 is of internal tapered form to guide the tube to an aperture 66 which closely fits the tube. The member 66 may be similarly tapered, and preferablythe fitting 63 and outlet member 62 are similarly tapered, the outlet member 62 having a relatively small aperture 6i, which fairly snugly fits the tube. -It will be noted that the members 60 and 66 t into opposite ends of the T fitting at the' entrance end of the unit, and the tting 68 and outlet member 52 connect into opposite ends of the T fitting at the outlet end of the' unit. The result is that when a tube is in the unit the several small apertures are substantially closed.

While on the subject of this quenching unit, it is thought best to describe the operation and linto the line function thereof before going into the description of other structurel. Therefore, assuming that a tube is moving through the device, as shownin Fig. 5, from right to left, and that oil under pressure is being forced through the pipe 15; this oil is trapped, so to speak, between the sealing joints 13. Therefore, the oil is forced through the apertures 64 into direct contact with the tube. The oil moves in opposite directions-some through the device toward the left into the outlet pipe 16 and some toward the right to the outlet pipe 11. The small` aperture 80 substantially prevents any oil from passing into the water jacketed unit. This action is aided by movement of the tube through the aperture 80. The outlet aperture 8| substantially prevents oil from leaking out of thev outlet end, although there may be some leakage at this point, due to the movement of the tube, but it does-not disturb the operation in any way. The tube may run through a wiper device 90 (Fig. 1) for wiping off excess oil. Thus the tube is completely surrounded by the quenching oil. At the same time a non-oxidizing condition is caused toprevail because the gases which enter through the pipe 50 are caused by said sealing joints to pass into the pipe 63 through the apertures 65, and this gas may burn oi at the burn off pipe 5| or the outlet end 8|,l or both.

By reference to Figure l the manner in which the oil is cooled will be appreciated. A suitable supply of water from the main 35 is directed through a pipe @l which then extends through coils 82 in a reservoir tank 93, the`water discharging through pipe 84 and drain 85. A suitable motor 96 drives a pump 0l, which pumps the oil from the reservoir through a pipe 96, Athence up through the pipe J5 to the quenching unit, and the oil returns to the reservoirthrough the aforementioned pipes 16 and 11.

As the tube passes out of the device it may pass between a set of rollers |00, some or all of which may be driven as by means of arbeit lill, preferably at a speed slightly in excess of that of tube movement. A out off device may be used for cutting the tube' into lengths where it is fed into the machine in a substantially continuous length, as for example, where vtube is formed of strip stock. A simple form of cut off vdevice is shown which may comprise a block |02 slidably mounted on a support |03 and acted upon by a coil spring |04 and carrying knives |06 operated by a manually operated lever |01. When the operator rocks the lever the knives c'ut the tube, and momentarily the block |02 is carried along with the tube. The operator releases the lever quickly and the block then moves back to its original position, as shown.

'I he cooling device, therefore, as will be observed, comprises in the main, a tubular structure, a section of which is water jacketed, and a section of which is a quenching unit. This tubular structure may be mounted on suitable supports ||0, which, together with other portions of the machine, are preferably mounted on electrical insulators as shown. The primary coil of the welding transformer is shown at -|20, one end f which connects directly to the lead line |2|. The other lead line |22 has a line |23 which connects to one pole |24 of a starter orstarting i switch, and line |25 connects to the other pole thereof, as shown at |26. Lead |22 connects to a cut out switch |28, which shunts out the starter and which, through a lead |29, connects directly shown in Fig. 4. One fornrof' a starting switch 'trolled by adjusting the valve |60.

|25. 'I'his is diagrammaticallyA and associated apparatus is shown in Fig. 6 where the starter comprises a tank |30 which may contain a suitable electrical conducting fluid and a plunger |3|. This plunger moves downwardly and the area of contact of the fluid and the plunger gradually increases, thus increasing current flow, until the plunger is at the bottom of f the container. At this time, however, the current 4is shunted around the starter by a knife switch |28. The plunger is advantageously operated by compressed air, for which purpose there is a cylinder |35 with a piston |31 therein. The piston rod is connected by a link |36 to a jointed lever |38, |38a fulcrumed at |39 and connected tothe plunger at |40. As shown in Fig. '1 the jointed arm comprises a part |38a normally latched to part |38` by a spring actuated hook |4I, which catches on a pin |42. This is the position shown in Fig. 6. The two parts are tensioned by a coil spring |43. As the piston moves upwardly the plunger is forced downwardly in the container until it is in its lowermost position therein at about which time the heel of the hook |4i strikes an abutment |44 and is rocked to release the pin |42, whereupon continued movement of the piston rocks |38a independently of movement of the part |38. The dotted line showing in Fig. 6 illustrates approximately the position of the parts at the time when the hook |4| is released from the pin. t'this time the blade of the knife switch |28 is out of contact with its contact member |45, and upon continued upward movement of the piston part |38a, is rocked and the knife switch closed, and thus the current is shunted across the knife switch to 'line |29 and line |25. Due to this arrangement, at. the start of the operation the welding current is relatively low, but it gradually increases as the plunger moves down into the receptacle. This is but one form of such a starting device. t will be understood that when the piston is caused to move downwardly the parts |38 and |38a of the lever again assume their interlocked relation.

vA controlling valve for the compressed air may be operated by a reciprocating or oscillating electric motor. The structures of such` electric motors are well known, and suffice it to say herein that it may have a reciprocating armature |50 pivotally mounted on a rock shaft and has a stator |52. The shaftJ extends, into a. valve housing |53, into which connects 'an air supply line |54, an eX- haust |55, an outlet |56 and an outlet |51, and in which is a valve member |58. Line |56 (Fig. 8)` is connected through the means of a'check valve |59 and another valve, which may be an ordinary hand controlled valve |60, to a pipe |6I, which leads to the bottom of the cylinder. lPipe |51 connects to a pipe |62, leading to the top of the cylinder, such connection being through. a check valve |63 and a valve |64 similar to valve |60. With the parts in the position shown in Figures 8 and 9 the compressed air is sent into the top part of the cylinder below the piston is'caused to exhaust therefrom through the valve |60, the exhaust being out the pipe |55. The speed of movement of the piston may therefore be conmotor armaturenshifts to the dotted line .posil tion shown in Fi'g..,8 the situation is reversed.`

The air passes to the bottom f the cylinder and out the top of the cylinder through valve |64; and adjustment of this valve may control theY speed. Accordingly, the valve |88, for example, may be adjusted for a slow upward movement of the piston, thus causing a slow movement of the starting plunger down into the container, and the valve |60 may be adjusted for a quick lift upwardly of the plunger.

Superimposed on Fig. 4 is a wiring diagram. The device is equipped with a normally open pilot switch |10 having an arm |1| equipped with a roller which the tube engages and raises as the tube enters the machine to close the switch. It has another normally open pilot switch |13 with anarm |12 which is engaged by and raised by the tube to close the same. In connection with this pilot switch there is a solenoid |14 in circuit with the welding circuit by means of conductors |15 and |18. So long as the welding circuit is energized the solenoid is energized and it attracts an armature |11, which is connected by a link |18 to the pilot switch |13. It will be appreciated that the tube is hot at the location of the arm |12 of the second pilot switch; therefore, the solenoid is provided to lift the arm |12 oi the tube during machine operation. These two switches are connected in series in a circuit off of the main power line and in series with a solenoid |80, which when energized, closes a switch |8| for the stator. This structure constitutes a relay. Conductors |82, |83 and |8311 are connected by the switch to conductors |84, |85 and |850. leading to the stator. for the pilot switch resides in a conductor |86 connecting to solenoid |80 and a conductor |81, which extends to a switch |88 opened and closed by the motor through the means of a rocker arm or the like |88; from the switch |88 a conductor |80 extends to the opposite side of the power line, as shown. 1

Adjacent the pilot switch |10 is a second pilot switch 200, which is normally closed, and which has an arm 20| to be engaged by the tube to open the switch. A conductor 202 connects this switch to one side of the power lline through the solenoid 203 for acting upon a switch 201. This constitutes a relay. A second conductor 20| connects to the conductor |90 through the means of a switch 205 which is opened and closed by a rocker arm or the like 208 actuated by the armature of the motor.

The operation is as follows: As a tubeenters the machine the switch pilot 200 is opened; the pilot switch |10 is closed; however, the closing of pilot switch |10 has no eilect until the end of the tube advances far enough to close the switch |13. At this time the motor and the arms |88 and 208 are in the position shown in Figs. 4 and 8; therefore, the switch |88 is closed, and as a result the solenoid |80 is energized. The action of this solenoid closes the switch |8| and the stator is energized, causing the armature to move to the dotted line position of Fig. 8, to shift the valve |58 to connect the compressed air line to the bottom of the cylinder and to connect the top of the cylinder to the exhaust.' And thus the plunger of the starting switch is moved downwardly into the liquid and the current gradually increases. Finally, when the plunger approaches the bottom of the container the double arm |88|88a will break and the switch |28 will then close and shunt out the starter switch. The welding circuit being energized also causes energization oi' the solenoid |14 so that the arm 121s lifted from the hot tube. This is to prevent anydamage to the tube surface, especially where the copper or other surface metal is ren- The circuit dered molten. In this action the motor armature swings clockwise, strikes the arm |88 and opens switch |88, thus deenergizing the solenoid |80, and the switch |8| will open. As the armature moves oiI of the arm 20E, the switch 205 closes, but the circuit for the solenoid 203 still remains open because the pilot switch 200 is held open by the tube. This condition maintains as long as tubing is being run through the machine.

When the end of the tube runs oi the switch member 20|, switch 200 closes. Thus the solenoid 203 is energized and the switch 201 is closed and the motor stator energized. This time the oscillating motor rocks in the opposite direction, thus reversing the air valve, causing the starter plunger |3| to be lifted yout of the liquid to break the welding circuit. Eventually, the armature rocks the arm 208 and opens the switch 205 with the result that the solenoid 203 is deenergized and switch 201 opens and the controlling circuit is dead. When the armature moved counterclockwise by reason of the closing of the switch 200, it will be understood that the arm |88 is released and the switch |88 closes. Therefore, the controlling circuit and switch positions are restored to their initial condition.

Briefly reiterating the operation, it will be noted that so long as there is no tubing or other element, which may be a wire, rod or strip, in the machine, the circuit for the oscillating motor, and the controlling circuits containing the pilot switches are dead; that the welding circuit is dead by reason of the position of the plunger of the starting switch. As soon as the tube enters the machine the reciprocating motor actuates to reverse the air Valve and after such reversal the controlling circuits again become dead by reason of the opening of the switch |88. The reversing of the air valve causes the plunger oi the starting switch to move into the liquid and the welding circuit is energized. As the end of the tube leaves the machine some of the controlling circuits are energized, the reciprocating motor operated in reverse direction to reverse the valve, the starting plunger lifts to break the welding circuit, and at the end of ,the oscillating movement of the armature, the controlling circuits are gin deenergized by the opening ci the switch Thereis an emergency switch 2|0 designed to be placed at a convenient location to be actuated by a machine attendant any time the machine is operating to bring it to a stop. When this switch is actuated it completes the circuit for the solenoid 203, and in fact shunts the current short of the switch 200. Thus the oscillating motor is reversed and it moves from the dotted line position shown in Figure 8 to the full line position, and when it reaches the end of its movement the switch 205 is opened and the current for the solenoid 203 broken. The switch 2|0 also has a contact member in circuit with the pilot switches |10 and |13, so that the circuit for the solenoid |80 is broken. Therefore, it will be noted that upon vactuation of the switch 2 l0 the welding circuit is cut oi!! the same as it is upon actuation of the switch 200; but as soon as the armature ,leaves the rocker arm |89 the switch 88 closes and due to the fact that the tube is in the machine the circuit for the solenoid |80 would be energized. However, this circuit is not energized until the switch 2 I0 is again operated or released by an attendant to close the circuit for the solenoid |80, at which time the reciprocating motor is energized and moves from of! position to on position, or in other words from the full line position to the dotted line position shown in Figure 8. The main line may have a main controlling switch 2|5 and the welding line may have a switch 2 I8. Such oscillating motors are available on the market and contain their own controlling mechanism and need not be detailed herein, and such mechanism forms no part of the invention, except that the motor, broadly, is an element in the combination of the entire apparatus.

An example of the operating conditions of the apparatus may be given with respect to the making of tubingv fashioned fromlv copper coatedA steel stock. The tube referred to in this particular example is of the type shown in my Patent No. 1,933,279 of October 31, 1933. The steel stock was copper coated by an electro-plating process and then fashioned into tubing. This tubing was then moved through the apparatus. perature attained by the electrical resistance exceeded copper melting temperature, with the result that the copper was made molten and the tube seam copper welded upon the cooling of the copper. The provision of the non-oxidizing and reducing gas prevented oxidation, and the resultant tube was copper coated. Tube was moved through the machine at the rate of about 45 feet per minute. The tube was 1/2 inch 'in outside diameter, and had a wall thickness of .035. The

rate of movement and metal mass, of course, is tol be co-ordinated with the cooling section.- In this particular instance, the water jacket was about 20 or 25 feet long and the oil bath or quenching unit was about 4 feet long. These dimensions, of course, may be increased where there is a greater metal mass or greater speed of movement, without departing from the invention. The water jacketed cooling unit brought the temperature of the tube down to somewhere around 700 F. from the copper melting temperature of about 1983o F. It would be impracticable to expose the copper coated tube to the atmosphere at a temperature as high as 700 F., as there would be a rapid oxidization of the copper. Likewiseitisimpractical to have a cooler,say for example a water jacketed coolerto do all the cooling, as at these temperatures and speed the cooler section would have to be so long as to make the device impractical. The rate of cooling decelerated with temperature decrease with the result that a cooler of great length would be required to cool the tube from say 700 F. to 200 F. Therefore, I have employed the quenching unit. The tube entered the quenching unit at about 700 F. and then was discharged therefrom and exposed to the atmosphere at a temperature of about 200 F., which is below the oxidizing temperature of the copper coated tube. These figures and dimensions are given as an example only, it being understood that the invention is not limited thereto.

The device is equally usable to anneal previously copper coated and copper welded tube, in which event the heat created by the resistance will be less than that of copper melting temperature. The same problem exists where such tube, being annealed, is copper coated because it must not be exposed to the atmosphere at high temperatures; and therefore the apparatus, including the water jacketed cooler unit and quenching unit, may be used in annealing such tube. Moreover,the apparatus may likewise be used in affixing by heat the copper coating on tube rods, strip stock, wire, or the like. In this regard tube or other lengths of material may be made The temof a basic metal other than steel, so long as the good example of this is Monel. Also the invention is not limited to use with copper coatedor copper welded lengths, as the same may be used with other metalswhere a cooling actionI is desired.

I claim:

1. In an apparatus for heating by electrical resistance a longitudinally moving relatively long length of metal comprising, longitudinally spaced electrodes, a closure for each electrode, a tubular structure connecting 1 the closures through which the strip of metal extends and including telescoping tubular members with a sealing slip ^joint, and means for adjusting one of the closure members with its electrode therein toward and away from the other closure member to vary the spacing between the electrodes.

2. In an apparatus substantially for the purposes described, means for passing a long length of metal lengthwise, spaced electrodes for engaging the metal at longitudinally spaced points, whereby the section of metal therebetween is heated by electrical resistance, an'electrical circuit for the electrodes, a switch for said circuit, means for actuating said switch, a controlling circuit, two pilot switches in series in the controlling circuit, each having an element engageable by the length of metal and movable thereby to close the same, with one lelement adjacent one electrode and one adjacent the other electrode, and means operable upon the closing of said controlling circuit by said pilot switches which results in an actuation of the switch actuating means ,to close the electrical circuit.

3. In an apparatus substantially for the purposes described, means for passing a long length lof metal lengthwise, first' and second spaced electrodes for engaging the metal in the order named at longitudinally spaced points, whereby the section of metal therebetween is heated by electrical resistance, an electrical circuit for the electrodes, a switch for said circuit, means for actuating saidy switch, a controlling circuit, two pilot switches in series in said circuit, one adjacent the rst electrode and one adjacent the second electrode and each having an element engageable and movable by the length of -metal to close said switches, whereby the controlling circuit is closed when the entering end of the length of metal reaches the pilot switch electrode adjacent the second and is opened as the rear end of the length of metal passes the pilot switch adjacent the rst electrode, and means operable upon the closing of the pilot switches and upon the opening of the ilrst pilot switch, which results in an actuation of the said means for actuating the switch for the electrode circuit.

4. In an apparatus substantiallyfor the purposes described, means for passing a long length of metal lengthwise, first and second spaced electrodes for engaging the metal in the order named pilot switches, the operation of which results in,y the actuation of the said switch actuating means for closing the switch for the electrode circuit, means for opening the controlling circuit while the said pilot switches remain closed, a second controlling circuit having a normally closed pilot switch held open by the presence of the length f of metal, `said second controlling circuit being closed by said last named pilot switch when the rear end of the length 0I metal arrives, a relay operated by the closing of the second controlled circuit, which results in the actuation of said switch actuating means for opening the electrode circuit, and means for opening said second controlling circuit subsequent to the closing thereof by the last mentioned pilot switch.

5. In an apparatus substantially for the purposes described, means for passingia long length oi' metal lengthwise, ilrst and second spaced electrodes for engaging the metal in the order named at longitudinally spaced points, whereby the section of metal therebetween is heated by electrical resistance, an electrical circuit for the' electrodes, a switch for making and breaking said circuit, a reciprocating control motor, a ,controlling circuit having a pair of normally open pilot switches connected in series, one adjacent the first electrode and one adjacent the second electrode, and both of which are closed by the presence of the length ofinetal in the apparatus, a, relay in the controlling circuit including a switch for the reciprocating motor, whereby the reciprocating motor is actuated'as the said controlling circuit is closed by the two pilot switches, another switch in said controlling circuit opened by the reciprocating motor substantially at one end of its said reciprocable movement, a second controlling circuit having a normally closed pilot switch `held open by the presence of the length of metal and which closes as the end of said length of metal passes thereby, a relay in said second controlling circuit including a switch for .the reciprocating motor, whereby the motor moves in areverse direction, another switch in the second controllingl circuit opened by the reciprocating motor substantially at the end of its second reciprocable movement, and means operated by the reciprocating motor to throw the switch ior the electrode circuit on and olf.

6. In an apparatus substantially for the purposes described, means for passing a long length of metallengthwise,` `ilrst and second spaced electrodes for engaging the "metal in the order named at longitudinally spaced points, whereby the section of metal therebetween is -heated by ling circuit having a pair of normally open pilot switches connected in series, one adjacent the ilrst electrode and one adjacent the second elec trode, and both of which are closed by the presence of the length of metal in the apparatus, a relay in the controlling circuit including a switch for the reciprocating motor, whereby the recip rocating motor is actuated as the said control ling circuit is closed by the two pilot switches, another switch in said controlling circuit opened by the reciprocating motor substantially at one end of its said reciprocable movementyrl second controlling circuit having a normally closed pilot switch held open by the presence oi the length of metal and which closes as the end of said length of metal passes thereby, a relay in said second controlling circuit including a switch for the reciprocating motor whereby' the motor moves in a reverse direction, another switch in the second controlling circuit opened by the reciprocating motor substantially at the end of its second reciprocable movement, means operu ated by the reciprocating motor to throw the switch for the electrode circuit on and 0E, and an emergency switch for manual operation connected in the second controlling circuit in parallel with the last mentioned pilot switch and having a switch member for breaking the first mentioned controlling circuit as the second controlling circuit is closed.

7. In an apparatus substantially for the purposes described comprising, moans for passing along length of metal lengthwise, first and second spaced ,electrodes for engaging the length of metal at longitudinally spaced points in the order named, whereby the metal therebetween is heated by electrical resistance, electrical control means including a pilot switch adjacent the first l electrode and a pilot switch adjacent the second electrode, and which are connected in a controlling circuit for energizing a circuit for the electrodes, said pilot switches each having an arm engageable by and movable by the length of metal when the same is in the apparatus to close said pilot switches, a solenoid connected across the electrode circuit, and an armature attracted thereby and connected to the, pilot switch adjacent the second electrode to lift the arm of said switch oil the metal which has been heated by electrical resistance.

BERT L. QUARNSTROM. 

